1. Field of the Invention
The present invention relates to an original-discrimination system and image forming apparatus, image processing apparatus and duplicator comprising the original-discrimination system. The original-discrimination system is described. There may be an act, for example, in which a special document, such as paper money, securities and so on is duplicated using duplicating means such as a digital duplicator. Thus, the special document may be forged on recording paper containing the duplicated corresponding image. As a method for preventing such an act, it may be devised that an original-discrimination system is previously incorporated in the duplicator. This original-discrimination system has a function of determining whether or not an image is of a special document such as a predetermined paper money, the image being used as a duplication original in the duplicating means. This duplicating means may comprise an arrangement in which duplication by the duplicating means is disabled if the original-discrimination system determines that the duplication original is the predetermined special document. By comprising such an arrangement, it becomes possible to prevent the above-mentioned forgery act.
2. Background of Related Art
As is well known, recently, image processing technology and image forming technology have been improved. As a result, it is possible for a special document such as a sheet of paper money to be duplicated using a color duplication device, for example. In this case, by this duplication, the corresponding image is produced on a recording paper. The obtained copy, that is, the recording paper on which the relevant image is produced and the relevant special document, such as a paper money, having been used as the duplication original in the relevant duplication, may closely approximate the original. In the extreme case, it may be difficult to distinguish between the copy and the special document.
In order to cope with such a situation as mentioned above, the above-mentioned original-discrimination system has been developed. One example of a method used in this original-discrimination system is disclosed in Japanese Laid-Open Application No.2-83571, Image Recording Device. In this method, a so-called Pattern Matching Method is used. This Pattern Matching Method is a general one as such a discrimination function. In the device in the above disclosure the input image signal is compared with previously registered pattern data. The input image signal comprises a signal corresponding to a duplication original and the registered pattern data is data corresponding to a special document such as a bill of paper currency, for example. As is well known, special documents such as a paper money are only printed by a designated organ and printing thereof by an unauthorized person, prohibited. As a result of the above mentioned comparison, a case where the input image signal is identical to the registered pattern data may be detected. It is then possible to prevent duplication of the duplication original corresponding to the input image signal, in this case, using the determination result.
Further, Japanese Laid-Open Patent Application No.60-229572 discloses Image Processing Apparatus using, as the criterion, image data itself of a determination-object paper-money acting a reference.
In an original-discrimination system such as above, there are the following problems: As is well known, images used in a special document such as paper money, for example, are extremely intricate. Further, to realize the image of the paper money, that is, to print the bill of paper money, various colors and intricate patterns are used. Accordingly, the amount of the above-mentioned pattern data, corresponding to the paper money in which the intricate and various colors and patterns are used, is very large. In order to store the thus large amount of data, a memory having a very large capacity is required accordingly. The thus very large capacity memory is required for the original-discrimination system. The original-descrimination system is extremely expensive. In addition, the comparison operation for determination, using the large amount of pattern data, is accordingly complex. The complex operation requires a correspondingly complex construction accordingly. Such a complex construction adds to the expense of the original-discrimination system. Furthermore, the original-discrimination operation using the complex construction takes a very long time to perform.
Also, since the manner in which an original acting as the determination object is placed on a platen glass of an apparatus such as a duplicator is chosen by a user, the manner may be predicted to be any manners. The placement manner relates to a placement position and placement angle (the original may be placed obliquely). This impossibility of placement manner prediction may also cause the construction of the relevant apparatus to be complex.
In an apparatus having such a complex construction, as described above, a considerable working time may be required for the relevant processing accordingly. As a result, real-time processing may not be possible. Real-time processing comprises a processing in which various processing required for the relevant duplication work may be smoothly performed without any delay in a case where an original is duplicated in a duplicator, for example. In these series of processing, data to be processed is processed soon after it is input without having to wait. Disablement of such a real-time processing may degrade the efficiency of the relevant apparatus.
Further, in an apparatus having such a complex construction, it may be difficult to immediately cope with the following cases, for example: A case where e new version of paper money is issued by the Bank of Japan; and a case where it is required to immediately deal with currencies and/or paper money of various foreign countries.
Another example of such an apparatus used for preventing a special document such as a paper money from being forged is disclosed in Japanese Laid-Open Patent Application No.2-210591. An image processing apparatus disclosed therein detects the placement condition of an original placed on a platen glass of the apparatus. The apparatus, using the detected placement condition, extracts only partial original-image data corresponding to a predetermined region of the original. Then, the apparatus compares this partial original-image data with reference image information previously registered in the apparatus. Then, the apparatus, as a result of the comparison, determines to what degree the partial original-image data and the reference image information approximate one another. Then, from the result of the determination, the apparatus detects whether or not the original placed on the platen glass comprises the relevant special document.
Further, this image processing apparatus detects four corners (that is, four vertexes of a rectangle, hereinafter) of the original placed on the platen glass. By the detection the apparatus detects the position at which the original is placed and the rotation angle at which the original is placed, as mentioned above. It is possible, for example, with the apparatus using a method such as mentioned above, to place a plurality of paper money bills of a same denomination on the platen glass such that there is no space between the paper money bills; and the bills are arranged in both vertical and horizontal directions. In this case, the apparatus detects the four corners of the contiguous entirety. Such four-corner detection may not enable detection of the four corners of each bill from among the placed plurality of bills. As a result, the position of each bill cannot be detected. As a result, this apparatus cannot detect that the bills comprise paper money.
Further, in such a conventional original-discrimination system, in a case where a paper money sheet is duplicated for example, if something such as an unexpected meaningless scribble mark exists on the paper money bill, for example, noise corresponding to the mark is included in its image data. Such an included noise may cause error discrimination in the original-discrimination system.
If the error discrimination is made in the original-discrimination system, duplication operation for the original image is halted and an incomplete duplication operation is thus performed on the original image which should not be prevented from being duplicated. As a result of such an incomplete duplication operation, an unnecessarily poor copy may be produced, or the above-mentioned halting of the duplication operation may cause shutdown of the duplicator itself, resulting in degrading of work efficiency in duplication work.
In Japanese Laid-Open Patent Application No.4-54681, a Color Image Processing Apparatus is disclosed. In this apparatus, a color original image is converted into the corresponding image data signal, and then the signal is output after being processed digitally. The image data signal is converted into predetermined code information and a histogram is produced, with respect to predetermined characteristics, using the code information, for a predetermined region of the color original image. By using this histogram, it is determined whether or not the color original image corresponds to a special document such as paper money.
However, in such an apparatus, since the determination is made in accordance with a histogram produced using only image data from a limited predetermined region, the discrimination accuracy is relatively low and thus error discriminations are liable to occur. Such error discriminations degrade work efficiency of work performed using the relevant apparatus.
Further, in such an original-discrimination system, the discrimination operation is particularly performed on image data input through a scanner. Therefore, the discrimination operation is not performed in a system in which another data inputting means is used for transferring image data corresponding to paper money or so.
Further, in such a conventional original-discrimination system, proper discrimination processing is not performed for all of various formats of image-data inputting. The various image-data inputting formats are, for example, the three color image data inputting formats in which image data is input as image data in each of three colors R, G, and B,or of three colors Y, M, and of four colors C, or Y, M, C and K. Further, in addition to classifications according to differences in color components, there are various inputting formats classified according to differences in data transfer systems as follows, for example: a system in which image data of respective color components are input in parallel; and a system in which image data is successively input, for each color element, in a so-called area sequence, line sequence, or point sequence.
Further, in such a conventional original-discrimination system, the higher the discrimination accuracy is made to become, the longer the time required for the discrimination operation becomes. As a result, in a case where the data replacement system is applied to a duplicator, the duplication operation requires a long time accordingly, resulting in degraded work efficiency original of the duplicator. Further, in such a conventional original-discrimination system, the discrimination accuracy is fixed even though differences in various duplication modes (single-color duplication and multi-color duplication, for example) are needed in the duplicator. However, the likelihood seems to be relatively low that a prohibited duplication act is carried out in the case of the above-mentioned single-color duplication mode, for example. Therefore, it seems to be possible to naturally reduce the discrimination accuracy for that mode. Maintaining the discrimination accuracy in such a case at the same level as that in other cases unnecessarily degrades the working efficiency original of the duplicator.
Technology regarding methods for processing image data which has been determined, by means of such a data replacement system, to correspond to a special document will now be described.
In Japanese Laid-Open Patent Application 2-288468, an Image Forming Apparatus is disclosed. This image forming apparatus performs certain processing on image data, to be used for a printing operation using specific printer toner color, from among the image data determined to be a special document. The above processing is such that image manipulation such as size modification, italicizing or obliquing, and/or mirroring operation, for example, is performed on the image corresponding to the image data to be performed the certain processing.
In Japanese Laid-Open Patent application No.2-210481, an Image Forming Apparatus is disclosed in which an output of an image is not carried out, the image corresponding to image data determined to correspond to a special document.
In Japanese Laid-Open Patent Application 2-171790, Color Duplication Apparatus Preventing Various Sorts of Paper Money from being Forged is disclosed, in which a toner-fixing property is intentionally degraded in printing image data corresponding to a special document.
In Japanese Laid-Open Patent Application No.2-73283, an Image Forming Apparatus is disclosed, in which a region of an image corresponding to image data is filled solid in printing using image data determined to correspond to a special document.
In such conventional methods, if the data replacement system makes a discrimination error so that the original image is determined to correspond to such a special document for which duplication is prohibited even though the original image is originally not one prohibited to duplicate, the following phenomenon occurs as a result: the copy of the relevant original image obtained has various image manipulations such as mentioned above performed on it. As a result, it is impossible to use the obtained copy for the original purpose, in particular, as a result of the above-mentioned solid filling processing being performed. As a result, wasting of a sheet of paper and working time occurs, resulting in degrading of cost-effectiveness.
Among such conventional original-discrimination systems, there is a system which uses, as its criterion, information concerning a seal mark region or a watermark region existing in an image associated with paper money. However, such a system does not have the capability of discrimination regarding an official document having neither a seal mark region nor a watermark region.